Dear Eyvaz Isaev: Thank you for your advice.My k-point is chosen by Xcrysden.such as: G 0.0000000000 0.0000000000 0.0000000000 K -0.7500000000 -0.3750000000 -0.3750000000 X -0.5000000000 0.0000000000 -0.5000000000 G 0.0000000000 0.0000000000 0.0000000000 L - 0.5000000000 -0.5000000000 -0.5000000000 X 0.0000000000 -0.5000000000 -0.5000000000 W -0.2500000000 -0.5000000000 -0.7500000000 L -0.5000000000 -0.5000000000 -0.5000000000
and I try to use your advice through using 3 type of attempt. 1.only chang K,Xpoint of K-G path to K(0.75,0.75,0), X point (1, 1, 0) 2.all k point multipy 2 times. such as: G 0.0000000000 0.0000000000 0.0000000000 K -1.5000000000 -0.7500000000 -0.7500000000 X -1.0000000000 0.0000000000 -1.0000000000 G 0.0000000000 0.0000000000 0.0000000000 L - 1.0000000000 -1.0000000000 -1.0000000000 X 0.0000000000 -1.0000000000 -1.0000000000 W -0.5000000000 -1.0000000000 -1.5000000000 L -1.0000000000 -1.0000000000 -1.0000000000 3.only K,Xpoint of K-G path multiply 2 times. such as G 0.0000000000 0.0000000000 0.0000000000 K -1.5000000000 -0.7500000000 -0.7500000000 X -1.0000000000 0.0000000000 -1.0000000000 G 0.0000000000 0.0000000000 0.0000000000 L - 0.5000000000 -0.5000000000 -0.5000000000 X 0.0000000000 -0.5000000000 -0.5000000000 W -0.2500000000 -0.5000000000 -0.7500000000 L -0.5000000000 -0.5000000000 -0.5000000000 However,all this attempts yield wrong picture. So,this must be something I didn't understand correctly.Would you tell me where is my fault ? 2011/5/6 Eyvaz Isaev <eyvaz_isaev at yahoo.com> > Hi, > > First of all I would recommend the use of PlotPhon utility to plot phonon > dispersion relations. For this one you have to have calculated interatomic > force constants matrix (*.fc) file. > > Regarding your particular question: you should choose K(0.75,0.75,0), then > from the K point go to the X point (1, 1, 0) which is equivalent to > the X(1,0,0) point. Then from the X(1,0,0) to the Gamma (0,0,0) point. > Dashed line just means that we can continue in this direction to match > phonons at the X point (i.e. it is an intermediate point from the Gamma to > the X point) . > > Please also provide your affiliation. > > Bests, > Eyvaz > > ------------------------------------------------------------------- > Prof. Eyvaz Isaev, > Department of Physics, Chemistry, and Biology (IFM), Linkoping University, > Sweden > Theoretical Physics Department, Moscow State Institute of Steel & Alloys, > Russia, > isaev at ifm.liu.se, eyvaz_isaev at yahoo.com > > > ------------------------------ > *From:* lucking-pine <songsong19840614 at gmail.com> > *To:* Pw_forum at pwscf.org > *Sent:* Fri, May 6, 2011 2:50:16 PM > *Subject:* [Pw_forum] why K-X point of phonon dispersion is wrong? > > My pwscf is used in calculating Si phonon dispersion.The trend of picture > in > > most special Symmetry is right.But the only K-X is wrong.I use Xcrysden to > > get K-point. > I found most paper is dash line in 'K' point.So what is mean? Please anyone > > > could tell me! Thanks! > The attachment is my picture and reference paper. > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110511/e5857d84/attachment.htm
